Radio receiving apparatus



Sept. 22, 1931.

a. Y. cuummsaun' RADIO RECEIVING APPARATUS and April 11, 1928 INVENTOR- E y J12 ATTORNEY Patented Sept. 22,

.- nnynnm-cnmrimes, an, or .srnr'nerrntn, nrssouar RADIO RECEIVING APPARATUS Application filed April 11,

My invention relates broadly to' radio receiving apparatus and more particularly to a simplified construction or radio receiver employing an electron tube circuit requiring minimum power consumptionfor reproduction of sign'alsat relatively large volume.

One of the fobjects of my invention is to provide a circuit arrangement for a radio re-' ceiving apparatus in which a single electron tube system may function as a regenerative circuit for the reproduction of signaling energy at relatively large volumewith mini mum powerconsumption.

Another object of my invention residesin the provision of an impedance in theinput circuit of an electron tube system cooperating With the impedance of the telephone headset orloud speaker in the output circuit of the electron tube system and with a capacity coupling circuit for facilitating the trans-e fer of energy between the input and output circuits of the electron tube system for re generative operation of the electron tube system.

Still another objectof my invention re-. sides in the circuit arrangementfor an electron tube system where losses in the electron tube system are minimized and the available signaling energy utilized to the maximum de.

gree for the reproduction of signaling energy, i

at relatively large volume in a single electron tube circuit. v 7

Other and further objects of my invention reside in the arran ement described more clearly in the specification hereinafter following and set forth in detail in the accompanying drawing.

In the circuit arrangement of my invention the receiving circuit is greatly simplified by utilizing a single electron tube in conjunction with a tuned circuit. for regenerative operation withoutthe usual hlgh potential source in the platecircuit. I make use.

of the impedance of the telephones in thecircuit'as a primary impedance of a system for transferring energy from the outputcircuit to the input circuit and introduce a secondary impedance in the grid circuit of the elecv tron tube system and then interconnect the two impedances by means of a radio freisas; Serial 1 To.:269,146.

tron tube and provide a variable resistance incircuit with the cathode and source of potential, across which a sufi'icient -drop' is produced for operating the plate circuit-of the electron tube. i

' Referring to the drawing in more detail, M i

' reference character 1 designates the antenna which is conductivelyco'upled to the grid" inductance 4 at a point 16, counting from the grounded end 17 of the grid inductance, that will put one-fourth of the inductance in the antenna circuit. Inductance i is tuned by a variable condenser When the capacity of 5 is increased, the wave-length of the antenna circuit is increased at the sametime the wavelength of the grid circuit is increased, resulting in a louder signal on the higher wave lengths because of closer resonance between the two circuits.

Reference character 3 higher inductance than is ordinarily used to produce regeneration and which produces the regenerative feedback to the grid circuit of tube 11. This inductance 3 in the plate circuit ofitube 9 has to be higher than usual becausebfthe low'plate' voltage. Thefilamentbattery 8 is one of approximately four and a half volts and is a standardbattery knownby its common use in radio receivingcircuits as a C battery. This battery not only supplies the" filament current for filament electrode 10 but the plate and grid current as well, the plate current being derived from the drop voltage across the variable filament resistance 7. The tube 9 is represented as having a grid 11 and aplate 12.

Reference character 1% refers to the telephones, and may in actual practice be either telephone receivers or a loud speaker. The device 14 performs the dual duty of reproducing the audible signals. and forming the primary of a double impedance reflex audio frequency amplifier. I 1 V The condenser 15 connects between one side of thewinding of thesound reproducerfl14 represents a coil of tioned between that end of the reactance 6 which is remote from the cathode 10 and the side of the sound reproducer winding of thedevice 14 which is remote from the cathode 10.

Reference character 6 designates the high impedance choke for passin audio frequency currents and forms the secondary of the douile impedance reflex audio frequency amplitier, and also serves as a grid leak. The Value of this impedance as a grid leak is low, but is su'iiicient in this circuit because of low plate voltage and makes the grid circuit perfectly stable in operation.

- A further improvement ollered by the use of ie telephones in my circuit arrangement is that there are no extra losses in the plate circuit due: to the-presence of the primary of an audio frequency transformer as would or dinarily be used in a reflex circuit. All of the audio frequency impedance in the plate circuit performsthe useful duty oi reproducing theaudible signals. 1

in the circuit arrangement of my invention the telephones serve the dual purpose of re roducins' the sound at the same time that thetelephones serve as a primary impedance of the double impedance audiofrequency re flex amplifier circuit thereby reducing electrical losses in the system and enabling reproduction of substantial olume from a singleelectron tube system. v r Y The circuit arrangement of my invention has produced extremely efficient results in practice, and while I have described a particular embodiment of my inventiom-I desire necting said grid and cathode electrodes, an output'circuit interconnecting said plate and cathode electrodes, means regeneratively coupling said input and output circuits, a cathode heating circuit including a variable resistance anda source of potential 1n series,

sound reproducer windings disposed in said output circuit, a connection between the positive side of said source and one side of said sound reproducer windings, a connection between the other ide otsaid' sound reproducer windings and said plate electrode, a react- I ance disposed between said tuned input circuit and said cathode electrode, and a condenser interconnected between an intermediate point in said tuned input circuit and said reactance and that side of said soundreproducer windings remote .from said cathode electrode. 7 i

In testimony whereofI ailix my signature.

BRYAN Y. GUMMINGSJPQ.

that it be understood that modifications may be made and that no limitations upon my invention are intended other than those imposed hy the scope of the appended claims.

lVhat I claim as new and desire to secure by Letters Patent of the United States is as follows: V v o 1. A radiorec-eivin system comprising an electron tube having grid, cathode and plate electrodes, a tuned input circuit interconnecting said grid and cathode electrodes, an output circuit interconnecting said plate and cathode electrodes, a cathode heating circuit including a source of potential and avariable resistor connected in series with said cathode electrode, sound reproducer windings disposed ins-aid output circuit, a connection from one side of said sound reproducer windings to said plate electrode, a connection from the other side of said sound reproducer windings to a point on said resistor, a reactance included between said tuned input circuit and said'cathode electrode, and acondenser interconnecting the end of said reactancegremote'from said cathode with the side of said sound reproducer windings remote from said electrodes, ELItllIlBd input circuitintercon- 

